Aerial propeller.



s'. LAWRENCE.

AERIAL PROPELLER.

APPLICATION FILED NOV. 23, 1909.

Patented May 2, 191-1.

SIDNEY LAWRENCE, OF MICHELDEVER, ENGLAND.

AERIAL PROPELLER.

Specification of Letters Patent.

Patented May 2, 1911.

, Application filed November 23, 1909. Serial No. 529,622.

To all whom it may concern:

' Be it known that I, SIDNEY LAWRENCE, a subject of the King of GreatBritain and Ireland, &c., residing at Micheldever, Hants, England, haveinvented certain new and useful Improvements in Aerial Propellers; and Ido hereby declare the following to be a full, clear, and exactdescription of the invention, such as will enable others skilled in theart to which it appertains to make and use the same. i I

This invention relates to improvements in aerial propellers which I soconstruct that during rotation variations of surface shape, and set orposition of the blades (relatively to the shape, and set or position ofthe'parts when at rest) occur automatically, being produced by, andfofadvantage under the working conditions prevailingffrom time to time,which conditions vary considerably. I find that neither rigid planes,nor those having merely general-flexibility (for example presenting whenflexed, convexity to the-atmosphere impinged upon) are satisfactory.

Any suitable propeller blades are in this invention used, their size,number, contour, material, relative positioning, and mode of mounting,being variable so far as consistent with features of this inventionhereinafter claimed. I

I makeeach blade'of material possessing rigidity in part, flexibility inpart, and resiliency in part, whereby the composite effect is that theblade surfaces during rotation vary more or less from their position andform when at rest. Thus the pitch alters;

arts which at rest were flat .planes become, under air resistance,concave, and parts which were concave become more so. The changesoccurring during propulsion will depend partly upon the speed ofrotation of the propellers, partly upon atmospheric conditions from timeto time, and partly upon the arrangement and construction of the bladein its at rest position. I pro- .vide blade framing which in largemeasure limits andcontro'ls the extent and nature of the aforesaidvariations.

Notwithstanding the mass of theory extent as to propelleraction, -I havenot found it satisfactory. Much of it is unreliable owing to failure totake all pertinent factors adequately'into consideration. Practicalexperiments having proved my improvements important, I'will withouttheoriaingexplain' embodiments of the invention as illustrated in theaccompanying drawings or diagrams. In the attached views, arrowsshow thedirection in which the propellers drive the aeroplanes or bodies towhich they would be attached. I use in some cases a series ofcomparatively small planes,blades or feathers to compose one largercombination blade or wing, and use a series of such wings on one boss.

Figure 1 shows a propeller wing comprising a plurality of feathers orplanes. Fig. 2

shows, on a larger scale, a blade as used to the number of two or moreextending from a a suitable boss, to constitute an aerial propeller.Fig. 3 is a plan view, and Fig. 4 an edge view, of the parts in Fig. 2.The blade tip is shown curved, but though not to such advantage,straight tips are usable. The preceding figures show at rest positions.Fig. 5 is an edge view showing an altered form which the blade of Figs.2 to 4 may attain when revolving. In thls view the direction of travelof the aeroplane or the like is however difierent from that in Fig. 2,as will be seen from the position of the boss attachment plate. Figs. 6and 7 illustrate sundry details which may be used. In Fig. 5 a variationof detail is also shown from the construction in Fig. 2.

To a boss a on a propeller shaft as 'b I fix attachment plates orterminals 0 of the blades.

d indicates a fastening screw; parts a to d are in practice of anypreferred construction; thus blades may have framing or inner endsintegral with the boss. Each blade has a webbing or filling w, and astrong rigid leading edge e, usually a metal or other rod,

' which either does not bend, or only bends to a negligible extent whenthe blades are rotated. It has or may have, however, a limited power oftwist or bend on its longitudinal axis, so that it shall have spring orresiliency toward the at rest position.

At or near the outer end a of arm 6 is attached'to-it, or integral withit, a spiral or other spring j, having an end continued to form orconnected to a rib or like member 9, forming the blade tip, or at aboutthe said This rib may be rigid or flexible and springy. I continue rib gto form a trailing edge h, or join it to such an edge, which extendstothe blade inner arm 7 which forms a rigid edge, though arm f 3 indicatesthinmetal forming a web attached at or near each end of rod 6. by eyesalong rigid edge 7,

as y, or in any suitable way. The blade body has in some cases springyribs m, m, or the like, to permit the flexion desired, insure strengthand promote resilience to the at rest position, or approximatelythereto. After the concaving occurring during flight, web it, especiallywhen of some materials, retains a little of the concavity so imparted toit. v

The blade in Fig. 2 is supposed to be at the top of its stroke and to beabout to turn with the tip descending in a direction away from theobserver. The air resistance would retard web as so that the concavitywould be on the side away from the observer. Each blade is fashioned sothat its outer or tiparea m slopes, or extends outward to a substantialextent, from the leading edge or arm end e Tip edge 9 may be integralwith the blade web, or consist of or include any suitable rod. As theblade of Fig. 2 rotates the composite influences aforesaid alter it,whatis shown in Fig. 5 illustrating this. As angle at at the blade root ispractically constant, theconcaving gradually increases from points i, j,toward tip area an, and point 1v. Air resistance retards the .tip areamaterially so that the said point and adjacent edges may take a positionas dotted at 71 Figs. 2 and 3. It is found that in some cases, as whenthe web is of fabric, and at some speeds, the area in the vicinity ofcorner m may not be concave to the air in front of it. Even someconvexity has occurred, for I find that whatever air resistance occursin front of the web will in some parts of it be noticeably modified bythe air effect on its other side. But the main effect on the forwardsurface of the web isby said air resistance, that is as to the largerpart of the web the making of concavity'as indicated; different parts ofthe web during flight becoming difi'e rently concaved or modifiedbecause of the controlling means provided as sprmgs 2 With a web of thinmetal as in Fig. 6, having a free edge 3 (except for links or the like ywhich allow the web to yield forwardly or backwardly)-the webfixed andthin and free along trailing edge h, and fixed also to a rigid or othertip-edge or outer edge 9 with only one spring j, I have found inpractice that at speeds I have employed a concavity occurs over thewhole web and is to some extent retained after stopping.

throughout my construction,

on the outer end of said radial Instead of spring 7', Fig. 2, a sleeveor cap I: is shown in Fig. 5 engaging rod 0 around which it will turn'somewhat according as air resistance retards the web. This device allowsof the yielding and concaving action, the desired resilience beingsecured by the action mainly of spring i.

Fig. 7 illustrates the use of a collar or ring 2' set at the end of theshort arm f when the construction is otherwise substantially as in Fig.2; the result being that j may be the only spring. Springs as j and imay have ends entering holes 111 or locked on the bars 6, f, as at 7'and such springs are in any suitable way, in some cases, so arrangedthat their tension or resilience can be regulated at will, as will bewell understood.

The collars 7c, 2' and various other parts may be modified in detail andarrangement while retaining their utility. Thus any rib as w may have aspring as 7' which will exert resihency in conjunction with any otherspring used as j.

In Fig. 1 three feathers or blades with webs m, :12", :2 are supportedby framing m, m at each side of boss a. The number of blades so placedfor each wing may be greatly increased at will. Details of these aresuch as are already indicated by reference to the other figures; but inaddition there is stepped setting of the blades; they do not overlap, ordo so only slightly. The outer ends of the wings are in advance of theinner ends, that is web m is more forward in the direction of flightthan web w, or :11.

-What I claim as my invention and desire to secure by Letters Patent ofthe United States is 1. In aerial propellers, the combination of acentral boss and pro eller blades each having a substantially rigidradial arm extending from said boss, a substantially ri 'd inner axialarm, an outer arm of greater ength than said inner arm and mounted toswing arm, and a flexible web supported by said inner and outer arms,substantially as described.

2. In aerial propellers, the combination of a central boss, a pluralityof win each comprising a substantially rigid radial arm extending fromsaid boss, a substantially rigid inner axial arm, a resiliently mountedouter arm carried at the end of said radial arm, and a flexible websupported by said resiliently mounted arm and said rigid axial arm,substantially as described.

3. In aerial propellers, the-combination of a central boss and pro ellerblades, each comprising a substantial y rigid radial arm extending fromsaid boss, a substantially rigid inner axial arm, a resiliently mountedouter arm carried at the outer end of said radial arm and of greaterlength than said axial arm, and a flexible web supported by said outerand inner arms, substantially as described.

4. In aerial propellers, the combination of a central boss and propellerblades, each comprising a radial arm extending from said boss, an inneraxial arm and a resiliently mounted framework connected at one end tothe outer end of said radial arm thence extending for a length greaterthan the length of said axial arm and then bent upon itself andconnected at its other end to the outer end of said axial arm, and aflexible Web supported by said resilient frame, substantially asdescribed. 1

5. In aerial propellers, the combination of a central boss, a supportextending radially from said boss and shapedto form a plurality ofradial arms offset from each other and provided with a plurality ofaxially disposed arms, outer arms of greater length than said axial armsand at their inner ends mounted to swing on said radial arms, andflexible webbing sup orted by said outer arms and axial arms, sustantially as described.

6. In aerial propellers, the combination -of a central boss, a supportextending radially from said boss and formed to rovide a plurality ofradial arms ofi'set rom each other and each radial arm being providedwith an axially disposed arm at its inner end, outer arms mounted toswing on the outer ends of said radial arms and of greater length thansaid axial arms, and flexible Webbing supported by said outer arms andaxial arms, substantially as dey scribed.

In witness whereof I have hereunto set my hand in the presence of twowitnesses. Y SIDNEY LAWRENCE.

Witnesses:

VERA BROOKSMITH, BEATRICE M. LOWE.

